US2252830A - Method and apparatus for dispensing gas material - Google Patents

Description

Aug. 19, 1941. L. A. BLISS; EIAL 'idETI-IOD AND APPARATUS FOR DISP E NSING GAS MATERIAL I Filed Ma 24, 1939 2 Sheets-Sheet 1 71 MMMMW 1941- 1. A. BLISS ETAL 2,252,330

METHOD AND APPARATUS FOR DISPENSING GAS MATERIAL Fi led May 24, 1939 2 Sheets-Sheet 2 ATTORNEXS Patented Aug. 19, 1941 METHOD AND APPARATUS FOR DISPENSING GAS MATERIAL Lyman A. Bliss, New York, and John J. Murphy,

Mount Vernon, N.

Y., ass

ignore to The Linde Air Products Company, New York, N. Y., a corporation of Ohio Application May 24, 1939, Serial No. 275,374

11 Claims. ((31. 62-1) This invention relates'to a method and apparatus for dispensing a gas material for industrial consumption, which has a liquid phase with a boiling point below 233 K. at atmospheric pressure, such as liquid oxygen, and particularly to the steps practiced and the receiving apparatus employed at consuming installations for eflecting relatively continuous conversion of gas material from the liquid phase into the gas phase and bringing it to a desired service pressure.

The invention has for its object generally the provision of an improved combination of steps, together with suitable apparatus, for handling a plurality of charges of liquefied gas of the character indicated in continuous succession over relatively long periods in a manner involving relatively little loss from blowdown and other causes.

More specifically, it is an object to provide a combination of procedural steps and coordinated apparatus for transporting and delivering gas material as a series of liquid charges for conversion into vapor in a vaporizing device through reception by a common receiving device installed at the place of consumption, whereby a relatively low average liquid temperature ion the gas material converted is maintained, providing a vapor at a relatively low pressure.

Another object is to provide suitable apparatus at consuming installations for receiving a series of charges of the liquefied gas for gasification, in a manner permitting their discharge from transport or other containers and their vaporization at relatively low pressures so as to avoid superheating.

Still another object is to provide a converting system for a series of liquid charges adapted for continuous service over long periods employing an improved heat cycle, involving the mechanical attainment of the desired service pressure whereby gasification of the charges and the subsequent compression of the gas phase maybe accomplished in a manner efiecting improved economies in the utilization of energy and in the apparatus employed for servicing moses.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the apparatus embodying features of construction, combinations of elements and arrangement of parts which are adapted to eflfect such steps, all as exemplified in the following detailed disclosure-and the scope of the invention 'will be indicated in the claims.

For a fuller understanding of the nature and objects 01 the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 is a view, partly diagrammatic and partly in vertical section, illustrating an arrangement of apparatus at a consuming installation for practicing the present invention;

Fig. 2 shows a plan view of the apparatus shown in Fig. 1;

Fig. 3 is a view similar to Fig. land shows a modification of an arrangement oi. apparatus suitable for practicing the invention; and

- Fig. 4 is an explanatory diagram.

Heretoiore, it has been proposed to supply gas for industrial consumption at a desired pressure from a charge or liquefied gas, which is transported to the consuming installation in a suitable vessel or container, the conversion from the liquid phase into the gas phase being accomplished mainly by the controllable admission of heat to the liquid phase. Various types of apparatus have been proposed for introducing the heat through both convection" and conduction. Where the container operates in conjunction with a continuously connected heat applying receiver so as to convert the liquid phase into the gas phase at a relatively high pressure, such apparatus has been commonly referred to as a cold converter.

Where the liquid phase is supplied to a receiving system having heating means from a container which is connected through a removable connection or through onehaving a valve whereby it may be shut off from the receiver and heat afterwards applied in a desired amount sufiicient to effect conversion of the gas material from the liquid phase into the gas phase at a relatively high pressure independently of any pressure originally obtaining in the discharged container,

such system has been generally referred to as a "warm converter."

It has also been proposed to provide systems in which the desired pressure is attained in part through the admission oi heat to generate a gas phase and in part mechanically by employing a pump, as taught in U. S. patent to Heylandt,

No. 1,824,889, but the pressure of the gas entering the pump involved superheating and the inefiicient use of ene gy; superhiting being invariably practiced in the gasification oi. a charge in all the above systems. Relatively large losses from blowdown in consequence resulted, the losses being multiplied with each delivery.

In accordance with the present invention, a substantially continuous supply of pressure gas is had over relatively long service periods with low losses by vaporizing the charges delivered successively to a consuming installation in such a manner as to maintain the gas material substantially at atmospheric pressure, whereby its initial low temperature is retained throughout gasiflcation and superheating is avoided. This is achieved in part by employing a common receiving device to provide a continuous supply at an average low temperature, the charges received being advantageously transferred to the device by gravity, together with a cooperating vaporizer that is controllably heated. The gas phase generated is consequently relatively cold and materially below the desired service pressure. This cold gas phase is thereupon elevated to the desired service pressure mechanically, by employing an external source of power. The common receiving device may with advantage be a container of a capacity slightly in excess of that of the transport container in order that the transport container may be closed and completely discharged at each service trip; for example, if the volume of the transport container be taken as unity, then that of the receiving device may be 1.2 times as great. Such common receiver, however, may take the form of a manifold constructed and arranged to permit a plurality of transport containers to be coupled for servicing at one time.

Referring now to the drawings and particularly to Figs. 1 and 2, I denotes generally a transport container which is shown as mounted on the chassis II of a truck that is backed up to a consuming installation or system. The system is shown provided with a manifold l2 which may be connected through a connection [3 to the bot tom of the container III for thepurpose of receiving a charge of the gas material in the liquid phase, such as a charge of liquid oxygen, which charge is to be gasified in the consuming system in order that the same may be supplied with gas at a desired pressure.

The charge delivered into the manifold I2 is conveyed from thence by a conduit H into a receiving device, here shown as a. heat insulated container l5 that has a capacity such that it can receive at one time the full content of the container Ill. The container l5 has associated with it a suitable vaporizing means, for example, an external heating coil, such as that shown at It, which is connected to the container [5 at points both above and below the normal liquid level of the container. This heating coil has its connection with the container l5 controlled by suitable valves as shown at lGa and l6b, in order to regulate the'heating. The heat applied to the coil It may be conveyed in any suitable manner, for example, by convection and conduction from an associated coil I! that is supplied with a suitable heating agent, such as steam. The flow of this agent is alsov shown as controllably circulated in the coil H.

In the system shown, the liquid phase is received at any suitable rate and converted into gas phase by permitting it to flow into the coil l6 at the bottom, while the vapor generated accumulates in the upper part of the container l5. Here, the extra capacity of container l5. readily accommodates the vapor generated, though care is exercised to keep the pressure substantially at atmospheric. A withdrawal connection I8 is pro- .a desired rate of discharge.

vided leading from the gas space of the container l5 for withdrawing the gas phase substantially as generated, such gas phase being relatively cold. A mechanical compressor I9 is introduced into this connection for accomplishing a desired elevation of the pressure of the gas phase to a value which may be somewhat above the desired service value to permit subsequent automatic reduction thereto, the compressor being driven from a suitable source of power, ,for example, from an electric motor as shown at 20. The withdrawal connection l8 may also have a suitable fiow controlling means therein, such as a valve Mia, and preferably includes a final gas phase temperature elevating means, such as a vapor heater 2|, by which the gas phase is further heated and passed at a desired high pressure to the consuming system. This latter is here shown as comprising one or more service pipe lines, such as that at 22, together with storage devices, such as those at 23.

Since the pressure in the container I5 is maintained at all times at a relatively low value (for example, with a permissible variation of less than 1 atmosphere above normal atmospheric), the liquid phase flowing into the container [5 is also under a low pressure and may discharge by gravity. Means, however, may be provided to insure Accordingly, container i0 is shown as provided with a suitable pressure building device, such as an evaporating coil 24.

In Fig. 2, the receiving manifold I2 is shown arranged to have a length suflicient and inlet connections numerous enough to afford the connection of two or more transport containers at a time. Such an arrangement permits a second truck with its transport container filled with liquid oxygen to arrive while one container is already coupled to the manifold l2 and discharging thereinto. The second container is coupled to the manifold l2 before the first container is disconnected, the second beginning its discharge as soon as that from the first has been'fully discharged. In the case of liquid oxygen, the supply to the system may be made as nearly substantially continuous as desired. In such case, the receiving container is kept substantially full, and

'heavy service demands for gaseous oxygen are readily met by the use of a plurality of trucks dispatched at proper intervals from the production plant tothe consumer. The use in the system of a receiver with a capacity, such as that of the second container here shown, operates to insure at all times an even supply of material to be gasified.

In the modification shown in Fig. 3, the transvport container is of a character adapted of itself I to generate a gas phase and simultaneously maintain a discharge into an external vaporizing device. Here, the transport container is shown at 30, mounted on the chassis of a truck 3| and is coupled to a receiving manifold 32 through a valved discharge connection 33. An evaporating coil 34 is provided on the container and a closable connection 35 provided that is normally adapted to vent evaporation products to the atmosphere, when the container is in transit.

The external vaporizer 36 is here connected directly to the manifold 32, the discharge connection 36x 01' the vaporizer leading to a mechanical compressor 31. This latter has an outlet to which is connected a service connection 38 leading to consuming devices. The service connection has a pressure regulator 39 interposed there- .the compressor is arranged to be coupled to a connection 42 leading from the gas space of the container 30. The connection 42 is here provided with a control valve and may communicate with the gas space through the connection 35.

The gas phase line, when so connected, permits container 30 to be operated bottled up, i. e., with connection 35 closed. Hence, there are no evaporation losses to the atmosphere. The gas withdrawn, or that generated at- 36, is fed to the compressor as cold gas. To this end, either a liquid or gas phase may be withdrawn from the container 30, as may be needed to keep the pressure on the container within the proper limits. Thus it is seen that when liquid phase is withdrawn, it is vaporized but not superheated, producing gas in the case of oxygen at about 90 K. The supplying of cold gas to the compressor decreases the amount of power required for its compression. This in turn operates to reduce the size needed for the compressor, and avoids the need for intercoolers and cylinder jackets.

In the arrangement shown in Fig. 3, the amount of material withdrawn at any time may be readily ascertained because the installation is shown as provided with weighing means, preferably in the form of platform scales, of a size such as to accommodate the transport truck. Here, the platform of the scales is shown at 45 operating a lever system 46 that operates indicating means, shown diagrammatically at 41. To ascertain the amount of gas material delivered, the truck is weighed 'before and after delivering a charge, in accordance with the stepstaught in the U. S. patent to Edwards, No. 2,044,673.

In the practice of the invention, each of the charges of liquefied gas, such as liquid oxygen, are preferably dispatched upon a schedule from the production plant to the consuming installation. Upon arrival, a container is coupled to the discharge manifold. This step is practiced with the transport container, whether it be the form of invention shown in Fig. 1, or that in Fig. 3. In Fig. 1-, the discharge may-take place under gravity; with the form in Fig. 3, this may take place against a slight head of pressure. When a container is empty, it is replaced by a full unit, and

returned to the production plant for refilling.

The evaporating coiL'shown at 34, is consequently preferably set into' operation substantially upon arrival at the consuming installation.

The elevation of the cold gas to a pressure of desired service value is shown as attained me I chanically in both forms of the invention. This ,not only permits the use of materials of construction'in the system, and particularly in the compressor, which are smaller and lighter than would otherwise be required,but has advantages in the heat cycle involved which may be seen from a consideration of the heat diagram shown in Fig. 4.

In Fig. 4, the abscissae represent entropy, while the ordinates shown temperature. The point A is taken on the liquid curve and represents the initial state or boiling point of a material, such as liquid oxygen, at 1 atmosphere of pressure. If -now heat be absorbed at constant pressure. the entropy of the substance increases and vapor is generated. This is drawn off and the state of the substance under these conditions is denoted by point B on the vapor curve. This gas or vapor is then superheated at constant pressure until a state, indicated by point C on the 1 atmosphere curve, is reached. 0n reaching ,this state the gas is compressed to the desired final pressure, which compression is advantageously practiced by employing more than one stage. This is here indicated by the broken line, which advances zigzag fashion until the desired pressure, such as 10 atmospheres, is attained. This state is denoted by point H on the curve, the substance having passed successively through the states denoted by intermediate points K, L and M.

If the liquid oxygen were initially placed under pressure and substantially heated so that it is brought from state A to that denoted by point D,

corresponding to a temperature of substantially K., latent heat may thereafter be absorbed with consequent increase of entropy until a state denoted by point E is reached, the substance bemg thereafter superheated at 10 atmospheres along the path EH until the final temperature desired is reached.

Where mechanical compression is employed, the withdrawn gas at low pressure, for example, in the state defined by point F at 1- atmosphere, and slightly heated, is passed into the compressor, such as that at I 9 or, and raised to the desired high pressure denoted by point J on the 10 atmospherecurve. The path FJ indicates. adiabatic compression, which, while ideal,

is not ordinarily encountered in practice, since the gas compressed is partly heated by friction and heat leak so that a point G on the curve EH is reached upon discharge from the pump. The final state H is then attained by a further input of heat, for example, as accomplished by coil 2|.

The cycle represented by the curve ABCH involves a certain amount of energy loss by reason of the final negative value of the entropy in passing from the state ,at C to the state at H, wh le the cycle indicated by the path ADEH employs less energy but is somewhat wasteful of high pressure gas material, due to blowdown. The cycle indicated by the path ABFGH not only avoids superheating of the stored liquid but is economical in the use of energy and also of the material itself.

While the invention herein disclosed has been illustrated in connection with the use of transport trucks, it is obvious that the invention is not so limited, and the use of railway transport containers is contemplated and accordingly deemed within the purview of the invention.

Since certain changes in carrying out the above method and in the, construction set forth, which embody the invention, may be made without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting 'riod a cold gas phase at a pressure not substanstallation through a common receiving device,-

vaporizing the series of charges received by controllably supplying heat to generate a cold gas phase at a pressure materially below a desired service pressure and without superheating, and then elevating to the desired service value the pressure of said cold gas phase by the use of mechanical compression. I

3. A method of dispensing gas material in a I liquid phase having a boiling point below 233 K.

at atmospheric pressure, which comprises transporting a series of charges of .the liquefied gas during a service period, delivering the same pursuant to a schedule to a consuming system through a common receiving device, vaporizing the series of charges successively by controllably admitting heat to generate a cold gas phase at a pressure not materially different from atmospheric pressure, and elevating to the desired service valve thepressure of said cold gas phase by means of a power-driven compressor.

4. The method of dispensing a gasmaterial in the liquid phase having a boiling point below 233 K. at atmospheric pressure, which comprises servicing a consuming system with a series of charges of liquefied gas from transport containers, providing the system with a liquid receiving capacity suflicient to receive a full charge at one time from a transport container, fully discharging a transport container when coupled to said system at a rate not less than that of the rate of vaporization, converting the liquid phase'received into a gas phase at a relatively lowpressure, and accomplishing mechanically the compression of the latter to a desired high pressure.

5. The method of dispensing a gas material in the liquid phase having a boiling point below 233 K at atmospheric pressure, which comprises servicing a consuming system with a series of charges of liquefied gas from transport containers, providing the system with a liquid receiving capacity suflicient to receive a full charge at one time from a transport container, fully discharging a succession of transport containers without appreciable interruption to said installation, converting the received liquid phase in the system to a gas phase at a relatively low pressure, and then compressing with external power said gas phase to a desired high pressure for industrial use.

6. The method of dispensing a gas material in the liquid phase having a boiling point below 233 K. at atmospheric pressure, which comprises servicing a consuming system with a series of charges of liquefied gas from transport containers, providing the system with .a-liquid receiving capacity suiiicient to receive a full charge at one time from a transport container, connecting and discharging fully each transport at said system, converting the discharged liquid phase in the system to a gas phase at a relatively low pressure without superheating, and then compressing said gas phase to a desired high pressure mechanically for industrial use.

7. The method of dispensing gas material in the-liquid phase having a boiling point below 233 K. at atmospheric pressure, which comprises transporting a charge of gas material in the liquid phase for delivery to a consuming installation, transferring the charge delivered to said installation at substantially atmospheric pressure, converting the liquid phase into a gas phase without superheating by controllably supplying heat at a pressurenot materially above atmospheric, and then elevating by mechanical energy the pressure of the gas phase generated to a desired high value.

8. In apparatus for dispensing gas material which has a boiling point below 233 K. at atmospheric pressure, a system adapted to be serviced by a transport container normally open to the atmosphere while in transit from production plant arranged to consumer's plant for supplying such gas material at a relatively high pressure for industrial consumption, said system comprising a storage container of capacity sufflcient to receive in one charge and without substantial pressure rise the entire contents of said transport container, external vaporizing means connected to said storage container, a gas pump, a conduit directly connecting the vapor space of said stor-' age container to said gas pump, and a second conduit adapted to receive the discharge from said pump provided with pressure modifying means therein, the heating capacity'of said vaporizing means being so correlated to the volumetric capacity of said storage container that the gas material is delivered from the vapor space of the storage container to said pump without materially raising the pressure in said storage container.

9. In apparatus for dispensing gas material having a boiling point temperature at atmospheric pressure less than 233 K., a system adapted to be serviced by transport containers normally open to the atmosphere while in transit from production plant to a consuming installation for servicing the same with gas material in the liquid phase, said system comprising a liquid phase receiving means and associated gas phase supplying connections, said liquid phase receiving means being constructed to have a volumetric capacity sufllcient to receive at one time and .without substantial pressure rise the entire charge contained in a servicing transport container, external vaporizing meangconnected to said liquid phase receiving means for converting liquid phase into gas phase, mechanically actuated pressure elevating means connected to receive said generated gas phase and deliver the same to said supply connections at a desired high pressure, and manifold means fortransferring thewcharge of gas material in liquid phase from a transport container to said liquid phase receiving means and provided with connections affording alternate connection with a plurality of transport containers; whereby each transport container upon disconnection from said manifold means may be replaced by another and has its charge of liquid phase replaced by a filling of gas phase which may be sealed in the transport container and returned to a production plant.

10. In apparatus for dispensing gas material having a boiling point temperature at atmospheric pressure less than 233 K., a system adapted to be serviced by transport containers normally open to the atmosphere while in transit from production plant to a consuming installation for servicing the same with gas material in the liquid phase, said system comprising a storage container for receiving liquid phase, associated gas phase supplying connections, said storage container constructed to have a capacity sufiicient to receive at one time and without substantial pressure rise the entire charge of a servicing transport container, external vaporizing means connected to said storage container for converting liquid phase into gas phase, mechanical pressure elevating means connected to withdraw the gas phase so generated and deliver the same to said supply connections at a. desired high pressure, and manifold means for transferring a charge of liquid phase from a transport container to said storage container when a service delivery is to be made.

11. In apparatus for dispensing gas material which has a boiling point below 233 K. at atmospheric pressure, a system including a container of desired capacity arranged for receiving and holding a desired charge or such gas material in the liquid phase, heating means connected to said container for building pressure therein, a conduit leading from the vapor space of said container, a gas pump connected to receive the discharge from said conduit, and a second conduit for conveying the discharge from said pump and pro vided with pressure modifying means therein. said heating means and said container being so correlated both in size and operative capacity that the gas material is delivered from the vapor space of said container to said pump without materially raising the pressure in said container.

LYMAN A. Buss. JOHN J. MURPHY.

CERTIFICATE OF CORRECTION Patent-No. 2,252,850. August 19, 19141.

LYMAN A. BLISS, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, first column, line 70,;for the word "shown" read --show'-; page 1.1., second column,

line 19, claimB, for "arranged to consumers plant" read -to consumer's plant arranged"; and that the said Letters Patent should be read with this correction therein that the same may confom to the record of the case in the Patent Office.

Signed and sealed this 50th day of September, A. D. 19in.

. Henry Van Arsdale, ($681) Acting cogrmissioner of Patents.

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